MICROELETTRICA MC30-BC, Руководство по эксплуатации

Страница: 14 / 37

MC30-BC
Doc. N°
MO-0365-ING
Copyright 2008 FW 980.09.01.X Date 15.06.2022 Rev. 1 Pag. 14 of 37
3.4 - IH (3F51) - Third overcurrent protection level
FuncEnab → Enable [Disable / Enable]
Options → BI Disable [Disable / Enable]
→
2xI Enable [Disable / Enable]
→ Trg Enable [Disable / Enable]
TripLev → IH 5.00 In (0.50  40.00) step 0.01 In
Timers
→
tIH 0.05 s
(0.05  60.00)
step 0.01 s
→ t2xI 0.10 s (0.02  9.99) step 0.01 s
Description of variables
FuncEnab : If disable the function is disactivated
BI : Operation controlled by Blocking Digital Input
2xI : Automatic threshold doubling on inrush
Trg : Function operation triggers the oscillographic wave form capture
(see § Oscillographic Recording)
IH : Minimum phase current pick-up level (limited to 40 times In)
t2xI : Trip time delay
tIH : Trip time delay
Trip when : The current trip level is exceeded for time “tIH”.
When the function is tripped : Signalization = Led “Trip” is illuminated
Last Trip = Is recorded
Function reset when : The current drop below 95% IH.
Led reset when : push-button is pressed
3.4.2 – Automatic doubling of Overcurrent thresholds on current inrush
For some of the phase Overcurrent functions (I>>, IH) it is possible to have the set trip level [Is] automatically
doubled when strong inrush current is detected.
If at circuit Breaker closure (i.e. when the input current rises from zero to a minimum measurable value) the
current increases from 0 to 1.5 times the rated value [In] in less than 60ms, the set minimum pick-up level
[Is] is dynamically doubled ([Is]
→ [2Is]) and keeps this value until the input current drops below 1.25xIn or
the set time [t2xI] has elapsed.
This functionality is very useful to avoid spurious tripping of the instantaneous or short-time delayed
Overcurrent elements that could be experienced at switch-on of reactive loads like Transformer or Capacitors.